Thermostatic cooling controls



L. D. TYSON THERMOSTATIC COOLING VCONTROLS Feb. 23, 1943.

Filed Nov. 5o,- 1940 INV ENT OR,

Patented Feb. V23 1943 as ortie THERMOSTATIC @@LING OONTR/LS Levi D. Tyson, Elkhart, Ind., assigner to International Machine Tool Corporation, a corporation o! Indiana 2 Claims.

The present invention relates to improvements in thcrmostatic cooling controls.

In application Serial No. 345,922, led by the present applicant on July 17, 1940, there are cie-l scribed improvements in thermostatic controls for ma-chine tools embodying mechanism for communicating heat in a controlled manner to machine tools or the like whereby uniform temperatures and consequently uniform dimensions may be maintained at lall times whether such machine tools or the like are idle or in operation.

The present invention is concerned with control mechanism for delivering cooling medium to those parts of machine tools or the like which tend to become heated when in operation.

`An object of the present invention is to provide machine tool mechanism having instrumentalities for simplifying the preservation of the settings of the parte regardless of the fact that such settings may be made when the mechanism is stationary.

A further objectLJs to provide machine tool mechanism having controlled cooling means for preventing the machine from departing `beyond prescribed limits from settings made when the mechanism is stationary.

A further object is to provide controllable cooling means for machine tool mechanism well adapted to meet the needs of commercial operation.

Further objects will appear as the description proceeds.

Referring to the drawingl YFigure 1 is a view in side elevation showing more or less diagrammatically a lathe embodying the principles of the present invention; and

Figure 2 is an electrical diagram illustrating an electrical arrangement which may be employed in the practice of the present invention.

unit 2t, and' connected to the cooling unit 20 is the motor pump 2i for delivering cooling iiuid to the inlet pipe i3. The cooling unit may 'be of any of the ltypes to be purchased in the open market, such as the ordinary electric water cooler; or if water mains are convenient cold water may be admitted directly from a water supply and discharged through the outlet pipe I9, in which case the motor 2l may operate a valve in the inlet pipe i8. The cooling passageways are, of course, independent of the lubricating system of the machine.

The numeral 22 indicates a thermostat positioned to be responsiveio temperature within the headstocl: i2. The electric circuit of the motor pump 2l and the thermostat 22 may be chosen as desired. Merely for the purpose of illustration, an electric circuit is indicated in Figure 2,

in which one electric'wire 23 is connected to one terminal of the motor 2i. The other terminal of the motor 2i is connected to one terminal of the thermostat 22. The other terminal, indicated by the numeral 24, of the thermostat 22 is connected through the switch 25 to the wire 26, constituting the other side of the electric circuit. Electrical connection between the wires 23 and 2l (assuming the switch 25 to be closed)` is controlled 'by means of the thermostat 22, which is adapted to close the contact 24 when the temperature in the vicinity of the thermostat reaches aprecietermined value but'which breaks contact with the contact 22 when a predetermined lower temperature is reached.

The mode of operationof the above described embodiment of the present invention is substantially as follows:

The numeral I0 indicates the bed of a lathe and the numeral I-I indicates the ways carried by said bed. The numeral I2 indicates the headstock provided with the rotating chuck I3 carrying a rotatable piece of work I4. The numeral II indicates a tailstook provided with the relatively stationary tool I6 adapted for boring a hole in the piece of work I4.

The headstock I2 is provided with cooling passageways, indicated generally by the .numeral I1. f

Cooling medium which may be Water, an antifreeze mixture, oil, or other liquid, is delivered to the cooling passageways l1' through the inlet pipe Il and is discharged through the outlet pipe Il.

The setting of the tool II and other parts oi the lathe may be made with the latheat rest and at room temperature or at any preferred temperature. The thermostat 22 will be So adjusted as to just break contact with the contactar 24 at this temperature. No further current is used until the temperature in the headstock I2, as indicated by the thermostat 22, rises slightly above the original temperature. The thermostat 22 will engage the contacter 24, completing the circuit The discharge pipe I9 leads to the cooling 55 through the motor pump 2i (assuming the switch 25 to be closed), thereby delivering cooling medium through the inlet pipe I3. cooling passageways I1 and the outlet pipe I9, bringing the temperature o1' the headstock I2 down to the value. for which the thermostat is set. When said headstock I2 has acquired this temperature the thermostat 22 will break contact with the contactor 24, stopping the operation of the motor machine continues diii'erent machines.

- mentioned, D equals pump 2i and the circulation of the cooling medium through the cooling passageways l1. The thermostat 22 will operate in the well understood manner to maintain the desired temperature within predetermined limits.

In explaining the applicability` oi the present invention to practical service it may be pointed out that in Figure 1 the dimension A is the height from the ways to the axis of rotation o! the chuck i3, B is the height from the ways to the cutting point of the tool i0, C is the radius of the cut. and D is the diameter of the cut.

The dimension A is changeable. of course, when the headstock varies from its initial tem perature. For example, at room temperature the dimension A may be exactly l0 inches. It

may be assumed that the dimension B is 8 inches; then D equals (10-8) 2=4.000 inches.

When the machine (not equipped .with the present invention) is started from room temperature the bore will be 4.000 inches, but as the to operate, the headstock de velops a running temperature which varies with Variations of from50 to l5 degrees are not uncommon. The metal ot the headstock therefore expands and. the dimension A may increase as much as .005 inch, orv even more. The dimension B does not change but romains at, 8 inches. Under the conditions just (10005-8) 2=4.0`10 inches, which is a serious deviation on many classes `ot work. turning cuts, and in the case oi a reamer it ls obvious that a true hole could not be reamed when the reamer gets out of line with the axis of the `rotating piece of work. -According to prior practice,l the operator has been required to change the adjustment oi his tool during the Similar errors would occur on condition, at which time the thermostat 22 breaks the circuit of the motor pump 2 l The temperature of the headstock is maintained constant within close limits, and consequently the relative placement of the cutting tool ii and the piece of work Il being operated upon is automatically maintained.

Though the above description has been directed more particularly to the matter of preserving the settings in a direction normal to the axis ot rotation of the chuck I3, it will be understood, of course, that the temperature control will also preserve settings in a direction along the axis of the chuck il.

Though the present invention has been described in connection with a lathe, it will be understood that it isalso applicable to other mechanisms wherein one part tends to heat up in operation while cooperating parts have less tendency to heat up.

'I'hough a preferred embodiment of the present invention has been described in detail, many modifications will occur to those skilled in the art. It is intended to cover all such modiilcations that fall within the scope of the appendedclaims.

What is claimed is: 1. In a machine, in combination, a tool member, a work holding member, one of said members entire warming up period, which may be from' one to two hours in duration. In the case of reamers. floating holders are used. Both expedients are objectionable.

AAccording to the present invention the (iii'il culties above referred to have been avoided. The settings ci the parts may be made with the headstock l2 at room temperature or at any preferred runningtemperaturc. At this point the' thermostat 22 is adjusted so that it just cuts out the current to the motor pump 2i. No further current i'.lo'ws until 'the headstock l! tends to heat up. in which case after the temperature v has raised a small amount the thermostat 22 cuts in the motor pump Il. bringing the temperature ofthe headstock I2 back to the desired running being rotatable relative to the other of said members, metallic means for supporting said rotatable member, means for communicating cooling medium to said supporting means, said communicating means being operable independently ot movement of eitherof said members and independently o! the lubrication system o! said machine, and thermostatic means directly responsive to the temperature oi the metal oi said supporting means for controlling the operativeness of said communicating means.

2. In a lathe, in combination, a metallic headstock, means carried by said headstock for rotatably supporting a piece` of work to be operated upon, a tool adapted to operate upon said piece o! work, means for communicating cooling medium to said headstock, said communicating means being operable independently of movement of either of said members and independently of the lubrication system of said machine,

and thermostatic means directly responsive to the temperature o! the metal of said headstock for controlling the operativeness of said com municating means.

y LEVI D. TYSCN. 

